Been on an absolute roll today, got 3 Dreamcast games working, all with one little tiny mark that seemed impossible to get out, after they had been polished the normal way, the normal way of using buffing pads, does not really get these odd very tiny deep marks sometimes found after a normal clean. What you need is one of these, Silverline 675223 Loose Leaf Buffing Wheel, 100 x 15 mm (their is an Amazon link on the first post).
The way they work, is the opposite way to normal buffing pads (flat 120mm bonnets), the part you buff with is round the edge of it, not the face side like buffing pads usually buff with. You can buff say one little mark much easier with one of these than normal, you still use shoe polish and need a drill, but once you have identified a particular mark on a disc, you can concentrate all the buffing effort on the one mark, instead of the whole disc. These buffing pads are also very good if you have a lot of scratches round the outside edge of the disc, working round the disc you can buff the outer edge very quickly with very good results, and it will get the scratches out very easy.
Today this is the buffing pad that got the 3 Dreamcast games to eventually work, once I was happy I had got each of the bad marks wiped out completely, I then polished it exactly as I would do normally, and got the surface as mint as I could then dumped it, and hey presto dumped fine no problems.
So if heavy scratches are the problem try these sort of puffing pads, then buff with the normal sort to make look pretty, the prettier it looks the better it dumps, it helps to have a magnifying glass so when you are on the final stage with the Novus2, you can see how the disc is coming along and when its finally as clean as you will ever get it. And that is pretty damn clean if you have sussed it out and have the right tools.
Anyway good luck with your cleaning, I am going to buy some "New Liquid Kiwi Neutral Polish" as soon as I can find something else to buy so I get free P&P, I will let you know if its any good or not.
Any one who wants to send me their discs, let me know, if cleaning is to much hassle for you, I would be glad just to add them to redump, as a dumper, don't mind sending them back if need be, as long as you can pay P&P.
He who controls the SPICE... controls the UNIVERSE!
The SPICE must flow.